OBJECTIVE: To compare economic value of two administration methods (self-injection and ambulatory care) of anti-rheumatoid biologics (etanercept) by application of cost-effectiveness analysis (CEA). METHODS: From societal perspective, we gathered cost data and outcome data. We developed decision tree model and applied Markov-model analysis. To estimate transitional probability, we used following data. Cost data: 1) direct cost: first visit fee and at-home care guidance fee (from health insurance fee schedule), drug costs (hypothetical costs - since etanercept is not admitted by Ministry of Health, Labor and Welfare (MHLW) yet), ambulatory cost (including transportation expenses. Data will be gained from "Rheumatoid tomonokai”, RA patients organization in Japan) and teaching cost of self-injection. (To estimate teaching cost, we developed a questionnaire for health care provider); 2) indirect cost: productivity loss. (Gained from MHLW) Outcome data: ACR20 (gained from 3rd phase of clinical trial data of etanercept in the US) and safety issues subject to self-injection (delayed finding ADR, accidentally impale needles to other people, and so on. Data will be gained from case report form (CRF)) as this is short-time analysis, we did not apply discount rate. We applied sensitivity analysis on 1) incidence of ADR, 2) safety data, 3) indirect costs.